Dishwashing machine



Dec. 17, 1963 F. w. BLANCHARD 3,114,375

DISK-[WASHING MACHINE Filed Jan. 22, 1962 5 Sheets-Sheet 1 Dec. 17, 1963F. w. BLANCHARD DISHWASHING MACHINE 3 Sheets-Sheet 2 Filed Jan. 22, 1962Dec. 17, 1963 F. w. BLANCHARD 3,114,375

DISHWASHING MACHINE Filed Jan. 22, 1962 3 Sheets-Sheet 3 United StatesPatent ()fi ice 3,114,375 Patented Dec. 17, 1963 3,114,375 DESHWASHINGMACHINE Frederick W. Blanchard, 4095 Broadway, Lachine, Quebec, CanadaFiled Jan. 22, 1962, Ser. No. 167,496 7 (Ilaims. (Cl. 134-138) Thisinvention relates to a dishwashing machine, and more particularly to adishwashing machine of what may be called the motor-less type, forhousehold use in washing plates, cups, tumblers, saucers, and flatware.

An object of the invention is the provision of a gen erally improved andmore satisfactory dishwashing machine of this kind.

Another object is the provision or" a machine so designed as to minimizethe escape of water at the cover of the machine, even though the lid orcover of the machine is not clamped or tightly sealed.

Another object of the invention is the provision, in a water operatedmachine without an electric motor, of improved water spray means forrotating the load of articles to be cleaned at an approximately constantrate of speed, notwithstanding substantial variations in the amount ofload in the carrying basket.

A further object is the provision of improved spray means so designedand constructed as to enable easy adjustment of the rotary speed of themachine, during the process of manufacture assembly, to produce thedesired rotary speed.

These and other desirable objects may be attained in the mannerdisclosed as an illustrative embodiment of the invention in thefollowing description and in the accompanying drawings forming a parthereof, in which:

FIG. 1 is a vertical section taken approximately diametrically throughthe entire machine and a fragment of a kitchen counter top or shelf inwhich it may be installed;

FIG. 2 is a fragmentary plan showing approximately one-half of theload-carrying basket which rotates within the machine, and showing alsothe spray tube and the spray orifices therein; and

FIG. 3 is a somewhat schematic fragmentary view, partly in elevation andpartly in vertical section, illustrating the angles of the varioussprays and their relation to the load-carrying basket.

.aohines of the motorless type are well known in the rt, a typicalexample being the machine shown in the resent applicants United StatesPatent 2,762,558, granted 'ebruary 22, 1955. The present invention maybe re -.rded as an improvement over the construction shown 11 applicantsprior patent above mentioned.

Experience with machines of this kind has demonstrated two difficulties,both of which are overcome by the present construction as hereindisclosed. The first difficulty is the matter of escape of water ontothe counter top. This could be overcome by providing an impervious coveror lid in tightly sealed relation to the body of the machine, but atight sealing arrangement requires various fastening means, sealingrings, and the like, which not only require some positive action by theoperator to lock or unlock or both, but are susceptible to damage byrough handling of the lid. Further, various jurisdictions have plumbingcodes or building codes relating to sealed essels diilicult to complywith in a machine for national distribution. For these reasons it isdesirable, as a practical matter, that the cover be allowed to remainloose or unclamped, but with prior constructions or loose covers ondishwashing machines, the-re has usually been considerable escape ofwater through the cover or onto the counter top. Such escape isminimized or completely eliminated by the present construction, asfurther described below, even though the cover of the machine is held inplace only by gravity.

The second difliculty which has frequently been encountered in the past,in machines of this general type, is the matter of maintaining thedesired speed of rotation of the basket containing the load of articlesto be washed. If the speed is too slow the basket tends to stall if thedishes and the like are not uniformly arranged. lf the'speed of rotationis too fast there may be ineflicient washing. Accordingly, there is anoptimum speed range at which the machine operates most efliciently. Forexample, in a machine having a basket of approximately 17 inches indiameter it has been found that the optimum range is from 40 to 60 rpm.and preferably 50 r.p.m. The main variable causing differences inrotational speed in prior dishwashers of this same general type, is thevariation in the size and distribution or" the load of tableware to bewashed. The distribution of the load usually has a greater effect uponthe speed of rotation, than the total weight of the load. The water jetarrangement of the present invention largely overcomes speed variationscaused by differences in load, as well as those caused by manufacturingvariations.

Referring now to FIG. 1 of the drawings, the machine in generalcomprises a main casing or tub having side walls ll. of approximatelycylindrical form, and a bottom 13 which is approximately list but whichslopes slightly toward the center where it is connected to a drain ordischarge conduit 15, the top of which is covered by a screen 17. Nearthe top or" the side wall ill, the wall is bent radially outwardly toform a horizontal flange at 19, then upwardly approximatelycylindrically as at 21, and terminates in another outwardly extendingradial flange 23 which may rest upon a counter top, shelf, or otherstructure 25' in which or on which it is desired to mount thedishwashing machine. In a typical installation intended for domestic useby a small family, the casing or tub 311 may have a diameter of about 18or 19 inches, and a depth from the top flange 23 to the bottom 13 ofabout 13 inches, but these dimensions are given merely by way of examplerather than by way of limitation.

When the machine is not being loaded or unloaded, the open top of thetub 11. is normally closed by a circular cover 31 in the form of a sheetof suitable metal (preferably aluminum) having a central depression 33at the center of which there is a knob or handle 35 for convenientgrasping to lift the cover. At its outer edge, the cover has a downturned cylindrical portion 37 which normally rests on the outwardlyturned horizontal flange 19' of the tub ill, in the position shown inFIG. 1. The outer diameter of the cylindrical portion 37 is sufficientlysmaller than the inner diameter of cylindrical portion 21 of the tub, sothat there is a slight gap 38 all the way around the cover, between themembers 21 and 37, when the cover is in normal closed position. This gap38 is preferably about /8 to of an inch, in a radial direction, andabout one inch in height, since the depth of the cylindrical portion 37on the cover is preferably about one inch, and the height of thecylindrical portion 21 between the horizontal flanges 19 and Z3 islikewise about one inch.

A variant of the construction just described is to extend the side wall11 to the full height of the machine, without a flange like presentflange =19, and terminating in a horizontal flange like the presentflange 23. In this case, an internal member such as a light channel orangle bar (not shown) could be attached to and run circumferentiallyaround the inside of the side wall 11, at the elevation of the presentflange 19, to form a support for the bottom edge of the portion 37 ofthe cover 31. One advantage of such alternative construction is thatinternal diameter of the main portion 11 of the machine can be therebyenlarged slightly without any enlargement in the size of the cover 31,by providing a diameter horizontally through side wall 11 of the samesize as the diameter horizontally through the cylindrical portion 2 1.

The cover 31 is preferably quite light, as owing to the constructionprovided herein there is no appreciable thrust tending to lift the cover31 upwardly when the machine is in operation. As already mentioned, suchfeature is of considerable advantage.

It may he helpful to discuss briefly the pressure which tends to buildup in a dishwashing machine of the present construction. As will bedescribed below, jets of hot water are used to Wash the dishes and suchhot Water and accompanying steam create vapor pressure inside themachine. In the case of a dishwashing machine permanently installed andconnected to the existing water supply and sewage system, the vaporpressure cannot escape freely through the drain 15 because of the backpressure caused by the usual trap in the sewage system. By contrast aportable machine having a drain tube or the like would not have the backpressure mentioned. Water poured down the drain easily overcomes thetrap back pressure, but such back pressure is nevertheless present andis quite sulficient to lift a cover of ordinary size and weight andpermit water to escape when the machine is in operation.

According to the present invention, this condition is overcome, and theescape of water is entirely eliminated by fitting the cover to the tubin the manner already described and by providing the downturnedcylindrical portion 37 of the cover with a series of circumferentiallyspaced small holes 39 located at about one-quarter of the way up fromthe bottom edge of the flange 37 to the top thereof. In one satisfactoryform of the machine the holes 3? are of an inch up from the bottom edgeof the cover flange. The number and spacing of the holes 39 are subjectto variation, but for a machine having the typical dimensions abovegiven, it is found that excellent results are obtained when the holes 39are about of an inch in diameter, and when about 60' of such holes areused, equally spaced around the circumference of the circular flange 37of the cover.

Preferably the under face of the cover 31 is provided with a layer 41 ofacoustical insulation material, such for example as a layer of syntheticfoam sheeting about A of an inch thick. This serves the additionalpurpose of helping to deaden the noise of operation of the machine.

When the machine is in use, vapor pressure created inside the machine isvented through the holes 39' into the gap between members 3 7 and 21 andthence to the atmosphere. In spite of the fact that inside the machinethere are several jets of hot water (to be described below) and aconsiderable amount of steam, the venting just described takes placewithout water ordinarily escaping, and with no tendency to lift thecover 31. The exact function is not presently known, but it has beenfound that the construction just described is very effective in keepingthe pressure inside the machine at substantially zero without allowingwater to escape.

Continuin with the description of other features of the machine, andstill referring to FIG. 1 of the drawings, centrally located at thebottom of the tub is a casting 51 which bridges over the central drainopening in a direction at right angles to the plane of the paper in FIG.1, and which is firmly secured at its two ends to the bottom wall 13 ofthe tub. Fixed to and supported by this casting 51 is the vertical pivot53 having at its upper end a hole for receiving and retaining thehardened steel ball 55 which serves as a bearing for the lower end of ahardened steel thrust bearing 57, the upper end of which is enlarged at59 and brazed, welded, or otherwise firmly secured to the upper end of atube 61 'which extends down the length of the pivot rod 53 almost to thebottom thereof, and which is slightly spaced laterally from the rod.Bearing sleeves 63 and 65 of low friction material such as oilimpregnated bushings, located near the top and bottom, respectively, ofthe tube 61, serve to bear lightly on the pivot 53 and to keep theremainder of the tube 61 spaced from the pivot rod.

Welded, soldered, brazed, or otherwise suitably secured around thebottom end of the tube 61, is a collar 67 having outwardly turned bottomflange 69, to which are welded or otherwise secured the inner ends ofthe approximately radial rods 71, the outer ends of which are bentupwardly as at '73 and secured at their upper ends to a circular ring75. These rods 71 have upstanding plate separator fingers 77 secured tothem, the spaces between the separators forming slots into which varioussizes of plates to be washed may be placed.

Any desired number of these arms '71 may be used. In a typical machinehaving the dimensions given above by way of example, there are eightsuch rods extending radially with respect to the central tube 61, andangularly spaced equally at 45 degrees from each other. Between certainof these main radial structures '71 there may be other supplementalradial structures such as the rods 81, the outer upstanding ends 83 ofwhich are secured to the same circular ring '75 above mentioned, and theother ends of which are bent into an inverted U-shaped structure 35' aswell seen in FIG. 1, to serve as supports for holding tumblers orsimilar hollow articles in inverted position. The radial inner ends ofthe structure 51 may be welded or otherwise fastened to a ring 87concentric with the tube 61, this ring also being fastened to andsupported by the main radial members 71.

A cup shaped holder 91 for the flatware to be washed (knives, forks,spoons, etc.) may surround the tube 61 concentrically therewith, and mayrest on and be supported by the radial members '71. The bottom of thisflatware holder is preferably in the form of a screen or otherforaminous structure 93, re-enforced by rings 95 and 97. The side walls'of the cup 91 may be either solid or foraminous, as desired.

Removably supported near the top of the tube 61 is a wire framestructure for holding cups or mugs in inverted washing position. Thiscup holder preferably comprises a central hub in the form of a tubularsleeve 161 loosely surrounding the upper portion of the tube 61 andsupported at the desired elevation on the tube in any suitable manner.For example, the lower edge of the sleeve 161 may simply rest on a lugor projection fixed to the outside of the tube 61 to project slightlytherefrom. Altcrnativcly, the upper end of the sleeve 181 may have fixedto it a diametrical pin 103 which rests loosely in a notch 165 formeddiametrically in the top of the member Various wires 1:17, 109, and 111,bent to the shapes shown and fastened to each other and to the hubsleeve 1511, serve as holders for supporting cups or mugs in invertedposition. The entire cup holder may be lifted upwardly off of the tube61, for ease in loading and unloading the plates, tumblers and flatwarein the space beneath. When the cup holder is again to be used, it issimply slipped over the top of the tube 61, and it settles down to theintended elevation.

All of the structural parts 57 to 111, inclusive, may collectively becalled the load basket or load carrier, and all of the tableware such asplates, tumblers, cups, latware, etc, placed in or on the load carriermay collcctively be called the load.

Near the bottom of the tub 11, at an elevation slightly below the bottomof the load basket, is a spray tube 1"1 extending approximately radiallyinto the machine, the inner end of the tube being held at or close tothe center of the machine by a suitable socket on the casting 51. Theinner end of the tube is closed as by means of a plug 123. The tubepasses approximately radially outwardly through theside wall 11 of thecasing, through a water tight collar ndicated in general at 125, and theouter end or the tube is connected in any suitable way to any suitablesupply of hot water. The connection to the water supply may be through aknown form of timing cycle mechanism, or through a manually controlledvalve, whereby the householder turns on the water supply to thedishwashing machine whenever desired, and leaves it on for such lengthof time as experience indicates is necessary for the proper washing ofthe load.

It is desirable that the machine operate at fixed pressure, and in amachine of the size indicated, such pressure would be about 40 poundsper square inch. This may be accomplished by providing a supply linehaving a pressure higher than the working pressure, say 60 p.s.i., andmaking use of a needle valve or other pressure reducing valve in thesupply line to adjust to the working pressure.

The above-mentioned spray tube 121 has orifices for issuance of spraysor jets of water, both for the purpose if impinging upon and cleaningthe various articles of the load, and for the purpose of rotating thebasket or load carrier so that all articles of the load are successivelyand repeatedly brought under the action of the jets or sprays. Theparticular location and arrangement of the jets or sprays constituteimportant features of the present invention.

Referring now to FIGS. 2 and 3 of the drawings, there are at least twoand preferably three different kinds of jets or sprays. First there isthe main series of jets, which may be called the propulsion jets, whichdo the main washing of the load and which also serve as the mainpropulsion force for rotating the basket. Second, there are the reactionjets or reverse jets which serve as brakes to prevent excessive speed ofrotation of the basket due to irregularities in loading, these jets alsoserving to help wash the bottom faces or under sides of the plates inthe load. Third, preferably there is also an additive propulsion jetserving the double purpose of insuring rotation of the basket even undersuch conditions of partial load that it would not otherwise rotate, andof enabling an adjustment or trimming of propulsive power to compensatefor variations in manufacture, as in the case of orifices not accuratelyplaced or having rough or burred edges, resulting in unpredictablepositioning of the jets of water.

The main propulsion jets are formed by a series of holes 131 drilled orotherwise formed radially in that part of the tube 121 which is withinthe casing or tub, at various predetermined intervals along the lengthof the tube. All of these jet orifices 131 are preferably in or veryclose to a plane extending axially along the center of the tube 121 andtilted upwardly and forwardly at an angle of preferably 18 degrees tothe vertical, plus or minus a permissible variation of one degree. Thejets issuing from these orifices 131 are shown schematically at 132 inFIG. 3. For a dishwashing machine having the typical dimensions abovegiven by way of example, there are preferably twelve of these propulsionjet orifices 131, not spaced evenly but spaced somewhat closer togethernear the outside of the machine, and progressively farther apart closerto the center of the machine in approximate inverse proportion to thedistance from the center of rotation. Thus if the jets are numbered insequence from the outer end inwardly toward the center, jets 2 and 3 area little farther apart than the spacing between jets 1 and 2, 3 and Sare still farther apart, 4 and 5 are spaced a little farther, 5 and 6are spaced still farther, and 6 and 7 have a still greater spacingbetween them. Jets 7 and 8 are spaced still farther apart than thespacing between 6 and 7. The

spacing between jets 8 and 11 is greater than the spacing between '7 and8, but in between jets 8 and 11 are the two extra jets 9 and 16, atlesser spacing, ecause it is found that at this point it is desirable tohave some additional water supply for additional assurance ofsatisfactory washing of cutlery in the holder hi, and of the tumblerssupported on the tumbler holders $5, and the cups or mugs supportedhigher up on the cup supporting 6 structure. The final or number 12 jet,closest to the center, is located at a point approximately midway, in aradial direction, between the tube 61 and the wall 91 of the flatwareholder, so as to throw a jet obliquely upwardly through the screenbottom of the flatware holder, to assist in washing the flatwaretherein.

The reaction jet or reverse jet orifices are shown at 133. In numberthey are preferably about one-third of the number of main or propulsionjets. Thus if the machine has 12 propulsion jets, as in the specificexample above, there are preferably four of the reaction jet orifices133. These orifices extend radially through the wall of the tube 121,and lie in or close to a plane extending along the axis of the tube 121and tilted 60 degrees rearwardly from the plane of the propulsion jets1312, so that if the latter are tilted at the preferred angle of 18degrees forwardly from a vertical plane, the reaction jets(schematically shown at 134 in FIG. 3) will be in a plane tilted 42degrees rearwardly from the same vertical plane.

The spacing of the reaction jet orifices 133 along the tube 121 issimilar to the spacing of the main propulsion jets, in that the jets arespaced increasingly farther apart from the outer edge toward the center.The first of the reaction jets (numbering from the outer one toward "thecenter) is approximately opposite the third of the propulsion jets, asplainly seen in FIG. 2, and in a position to impinge upon plates placedin the first or second slot (counting from the outside inwardly towardthe center) of the plate separator structure. The second reaction jet isapproximately opposite a point midway between jets 5 and 6 of thepropulsion series, in position to engage plates in the third slot of theplate separator structure. The third reaction jet is spaced a littlefurther inwardly beyond the seventh of the propulsion jets, in positionto impinge approximately on plates in the innermost one of the slots ofthe plate separator structure. The last or fourth one of the reactionjets is opposite a point between jets 1i and 11 of the propulsionseries, as seen in HS. 2. This jet will react against tumblers on thetumbler supports 35 as they swing around toward the spray tube 121.

The third type of jet, the additive propulsion jet, is not formed merelyby a'radial hole in the tube 121, as Was the case with the other jets,but is preferably formed by a short tube 135 having its inner endfastened tightly in an opening in the tube 121, the jet tube 135extending outwardly a distance of about A1 of an inch to A1 of an inchradially from the periphery of the tube 121. This additive jet tube 135is made of metal which is reasonably stiff to retain its shape in use,but which is nevertheless slightly bendable by exertion of reasonableforce. Brass or bronze tubing of about inch external diameter issuitable for this purpose, and the outer end of the tube preferably hasa portion of reduced internal diameter as shown in FIG. 3, to produce anozzle elfect, providing a jet or stream in a definite predetermineddirection such as shown schematically at 13%.

This additive jet tube 135 is initially manufactured and assembled at aforward angle or tilt of 60 degrees to the vertical (plus or minus onedegree), and is located about two-thirds of the way out from the centerof the machine toward the outer edge of the load basket. Preferably thejet tube 135 is so placed and directed that its jet impinges on a partof the basket structure, such as on the shaded areas M1 (FIG. 3) of thearms '71, '73 and the separators 77. Thus it provides a rotational forceor thrust even when there is little or no load in the basket to beimpinged upon by the main propulsion jets 132.

Although jet tube has been shown and described, it should be understoodthat alternative construction is possible. A simple hole drilled at theangle and position indicated for tube 135 will be approximately correct,considering the fairly large permissible range of rotational speed ofthe basket, and by carefully selecting the size of such drilled hole bymanufacturing experience, results very close to that achieved by jettube 135 can be attained.

Also, instead of one drilled hole as an alternative to jet tube 135,there may be two or more drilled holes spaced relatively close togetherin the same plane relative to the axis of spray tube 21.

As already indicated above during the general discussion, it isdesirable that the load basket in a machine of this type rotate at anapproximately constant speed notwithstanding variations in the characterand distribution of the load of articles to be washed. In practice, in amachine having the dimensions given above by Way of example, it is foundthat best results are obtained when the basket rotates at from 40 to 60revolutions per minute, as already mentioned, and the presentconstruction efliciently produces this rotation.

A factor to consider is that in a machine of this type, better and moreeificient washing is obtained if the propulsion jets are nearlyvertical, since this gives better assurance of the jets reaching allparts of the surface of each plate or dish, since the plates themselvesare nearly vertical in the notches of the plate separator structure '77and are arranged approximately tangent to successive concentric circlesaround the center post 53. Typical sizes of plates are indicatedschematically by the broken circles 151 in FIG. 3. The nearly verticaldirection of the jets also gives greater assurance that jets will reachhigh enough to cleanse the cups in the cup holder structure 107, 109,111 and to reach and cleanse the top edges of the largest plates 151. Atthe same time, the number of jets should be kept down to the minimumrequired for adequate cleansing, because every additional jet means agreater use of hot water, and added expense both to procure the waterand to heat it.

If one is trying to minimize the number of propulsion jets for the sakeof economy in use of hot water, then these jets must be placed at aconsiderable angle to the vertical, in order to assure sufiicient rotarypropulsive force to turn the basket under the most unfavorable loadconditions and the most unfavorable water pressure con- '(lJilOIlSlikely to be encountered in practice. This produces a loss in efiiciencybecause the jets are not so nearly vertical as would be desirable. Butthe present invention overcomes this, because the additive jet 136 canbe relied upon for a good deal of the propulsive or rotary force needed,so that the main series of jets 132 from the orifices 131 can be swungupward to a more nearly vertical position with the attendant advantagesand eificiencies of such nearly vertical position. As already indicated,the main jets are preferably at an angle of only 18 degrees to thevertical, which is a considerably lesser angle than with comparablestructures in the prior art.

Moreover, the making of the additive jet orifice 135 in the form of abendable tube is an important feature because the tube can be bent bythe person testing the machine during manufacture, to vary the positionof impact of the additive jet to a slight extent, to allow formanufacturing variations. Moreover, in the case of extra low waterpressure at various locations, a plumber can also make use of theadditive jet 136 to cause the machine to operate. Otherwise, there wouldbe danger that the machine would not operate at all if the availablepressure is far below the working pressure. This adjustment would bemade by trial, the plumber observing the rate of rotation of the basketand then taking a pair of pliers and bending the tube 135 a little oneway or another, to make the jet or stream 136 issuing therefrom impingemore or less on one part of another of the basket, until the desiredspeed of rotation of the basket is attained, under normal water pressureconditions at the location where the machine is installed. If normalwater pressure condrtrons at that location are later altered (as forexample by installation of a new pumping station, or new water mains toserve an area inadequately served previously) then the plumber can againbend the tube 135 as may be necessary to adjust the speed of rotation,the tube 135 thus acting as a trimmer means for close adjustment.

The additive jet 136, being set to impinge on the structure of thebasket at a substantial angle to the vertical, assures rotation of thebasket even under adverse load conditions of light load or no load.Under full load conditions, where there are more articles to be impingedby the main propulsion jets 132, there would be a greater tendency ofthe basket to speed up and go too fast, but this is counterbalanced andovercome to a very great degree by the reaction jets 134 issuing fromthe orifices 133, which react against the same articles in the load, ina reverse direction, tending to slow them up as well as impinging uponand washing other surfaces not reached by the main jets 132. The morearticles there are in the load to be impinged by the main jets toproduce greater propulsive force tending to turn the basket, the morearticles there will be to be impinged by the reaction jets 134. Inactual practice, it is found that this arrangement is remarkablyeffective in keeping the basket at an approximately constant speed ofrotation, under all load condiions from just a few articles to bewashed, up to a full load with all spaces filled. As already indicated,the reaction jets are fewer in number than the forward propulsion jets,but they are spaced so as to impinge on definite predetermined articlesof tableware.

This combination of forward propulsion jets at only a slight angle tothe vertical, along with reaction jets in a reverse direction at agreater angle to the vertical, and with an additive propulsion jet at astill greater angle to the vertical in a forward direction, is found togive excellent results also in keeping a constant speed of rotationduring any water pressure variations which may o cur from moment tomoment during the day. In the some way that the reaction jets tend toslow down any excessive speed that might be caused by impingement of thepropulsion jets on a greater number of articles than would be the casewith only a partial load, so also the reaction jets tend to slow downany increase in the speed of the basket that may be caused by anincrease in the water pressure. If the water pressure increases, theforce of the forward propulsion jets increases but the force of therearward reaction jets also increases, and vice versa if the pressuredrops.

The use of reverse jets along with forward jets has been suggested inthe prior art, but in all of the prior suggestions so far as now known,the jets have been arranged in a rather haphazard manner, with noattempt to have the jets carefully thought out and arranged to performspecific purposes or functions as is done in the present construction.The construction as herein disclosed results in a superior machine ofhigh efiioiency.

The orifices 131 of the propulsion jets 132 and the orifices 133 of thereverse jets 134 are preferably all of the same size, so that all ofthese jets are of the same power or force, considering them merely asjets per se, without regard to their spacing and direction. Of coursethe force that any jet exerts on the basket, tending to rotate it, willvary (1) approximately in proportion to the sine of the angle of tilt ofthe jet relative to the vertical, and also (2) approximately inproportion to the radial distance of the jet outwardly from the axis ofrotation of the basket, and (3) will be further influenced by thevarying angle at which the jet strikes a part of the basket or a surfaceof a plate or other article of tableware in the basket at any givenmoment during the rotary travel of the basket.

As for the first of the factors above mentioned, the sine of '18 degrees(the preferred forward tilt angle of the propulsion jets 132) is 0309,while the sine of 42 degrees (the preferred rearward tilt angle of thereverse jets) is 0.669, more than twice as great. However, it must beremembered that there are more than twice as many (preferably threetimes as many) propulsion jets as there are reverse jets. Also thepropulsion jets are more heavily concentrated at greater radialdistances from the axis of rotation (second factor above mentioned), the

net result of the first and second factors being that the jets givegreater forward propulsive force than the rearward or reverse thrustforce. The third factor is unpredictable, varying from load to loaddepending upon the exact placing of the plates and other articles. Thefinal net result of all the factors, as ascertained by extensivetesting, is that the preferred jet arrangement herein disclosed givesexcellent results and very satisfactory, efiicient, and economicalwashing of the tableware.

It is seen from the foregoing disclosure that the above mentionedobjects of the invention are well fulfilled. It is to be understood thatthe foregoing disclosure is given by way of illustrative example only,rather than by way of limitation, and that without departing from theinvention, the details may be varied within the scope of the appendedclaims.

What is claimed is:

l. A dishwashing machine comprising a housing, a tableware-carryingbasket mounted within said housing for rotation about a vertical axis, aWater spray tube extending approximately radially within said housingbelow the bottom of said basket, a first series of jet orifices atspaced intervals along said tube to provide a series of main propulsionwater jets issuing from said spray tube and directed obliquely upwardlyand forwardly substantimly in a common plane tilted forwardly at arelatively small angle to the vertical, a second series of jet orificesat spaced intervals along said tube to provide a series of reactionwater jets issuing from said spray tube and direoted obliquely upwardlyand rearwardly substantially in a common plane tilted rearwardly at amuch greater angle to the vertical than the forward tilt of the mainpropulsion jets, the jet orifices of the second series beingsubstantially less in number than those of the first series, andadditional orifice means on said spray tube to provide an additivepropulsion jet directed obliquely upwardly and forwardly at an angle tothe vertical substantially greater than the angle of tilt of either ofthe first two series of jets, said additive propulsion jet beingarranged to impinge upon successive portions of said basket to providesufiicient propulsive force to insure rotation of said 10 basket undersuch load conditions that impingement of said main propulsion jets onthe load of tableware in said basket would not by itself rotate saidbasket at a desired speed.

2. A construction as defined tlfl claim 1, wherein the angle between thecommon plane of the jets of the first series and the common plane of thejets of the second series is substantially degrees.

3. A construction as defined in claim 1, wherein the angle between thecommon plane of the jets of the first series and the direction of theadditive propulsion jet is substantially 42 degrees.

4. A construction as defined in claim 1, wherein said additional orificemeans includes a branch tube leading laterally from said approximatelyradial spray tube and being of bendable material so that it may be bentto produce exact adjustment of the direction of the jet issuingtherefrom.

5. A construction as defined in claim 1, wherein there are more thantwice as many jets in the first series as in the second series.

6. A construction as defined in claim 1, wherein there are approximatelythree times as many jets in the first series as in the second series.

7. A construction as defined in claim 1, wherein at least some or thejets of the first series and of the second series are spaced atprogressively increasing distance from each other, inwardly from theoutermost jet of each series toward the axis of rotation of the basket.

References Cited in the file of this patent UNITED STATES PATENTS1,574,452 South Feb. 23, 1926 1,620,671 Merseles Mar. 15, 1927 1,633,803B-allin June 28, 1927 2,124,052 Clough July 19, 1938 2,426,291 AbramsAug. 26, 1947 2,642,369 Hunter June 16, 1953 2,702,558 Blanchard Feb.22, 1955 3,060,946 Lantz Oct. 30, 1962

1. A DISHWASHING MACHINE COMPRISING A HOUSING, A TABLEWARE-CARRYINGBASKET MOUNTED WITHIN SAID HOUSING FOR ROTATION ABOUT A VERTICAL AXIS, AWATER SPRAY TUBE EXTENDING APPROXIMATELY RADIALLY WITHIN SAID HOUSINGBELOW THE BOTTOM OF SAID BASKET, A FIRST SERIES OF JET ORIFICES ATSPACED INTERVALS ALONG SAID TUBE TO PROVIDE A SERIES OF MAIN PROPULSIONWATER JETS ISSUING FROM SAID SPRAY TUBE AND DIRECTED OBLIQUELY UPWARDLYAND FORWARDLY SUBSTANTIALLY IN A COMMON PLANE TILTED FORWARDLY AT ARELATIVELY SMALL ANGLE TO THE VERTICAL, A SECOND SERIES OF JET ORIFICESAT SPACED INTERVALS ALONG SAID TUBE TO PROVIDE A SERIES OF REACTIONWATER JETS ISSUING FROM SAID SPRAY TUBE AND DIRECTED OBLIQUELY UPWARDLYAND REARWARDLY SUBSTANTIALLY IN A COMMON PLANE TILTED REARWARDLY AT AMUCH GREATER ANGLE TO THE VERTICAL THAN THE FORWARD TILT OF THE MAINPROPULSION JETS, THE JET ORIFICES OF THE SECOND SERIES BEINGSUBSTANTIALLY LESS IN NUMBER THAN THOSE OF THE FIRST SERIES, ANDADDITIONAL ORIFICE MEANS ON SAID SPRAY TUBE TO PROVIDE AN ADDITIVEPROPULSION JET DIRECTED OBLIQUELY UPWARDLY AND FORWARDLY AT AN ANGLE TOTHE VERTICAL SUBSTANTIALLY GREATER THAN THE ANGLE OF TILT OF EITHER OFTHE FIRST TWO SERIES OF JETS, SAID ADDITIVE PROPULSION JET BEINGARRANGED TO IMPINGE UPON SUCCESSIVE PORTIONS OF SAID BASKET TO PROVIDESUFFICIENT PROPULSIVE FORCE TO INSURE ROTATION OF SAID BASKET UNDER SUCHLOAD CONDITIONS THAT IMPINGEMENT OF SAID MAIN PROPULSION JETS ON THELOAD OF TABLEWARE IN SAID BASKET WOULD NOT BY ITSELF ROTATE SAID BASKETAT A DESIRED SPEED.